It is well-recognized in the field of environmental science that contamination of the subsurface by toxic substances is a significant problem. There exists a need for improved detection and characterization of underground contamination. In particular, it is known that non-aqueous phase liquid (NAPL) contaminants have been introduced into the subsurface by events such as pipeline leakages, improper waste disposal, and leaking storage tanks. These NAPL contaminants pose a significant hazard to human and environmental health. Because NAPL contaminants may be highly toxic, it is important to be able to detect and characterize instances of contamination that may affect groundwater so that appropriate remediation approaches may be developed.